How to tell the difference between breakthrough bleeding and the start of the period

How to tell the difference between breakthrough bleeding and the start of the period

I started taking Yasmin on the first day of my last period. I have to admit that it was lighter and less painful than usual but after 7 days (which is the normal length of my period 6-7 days) the heavier bleeding stopped and the spotting started ... brown discharge each and every day; i change panty liners 2-3 times a day .. before using Yasmin this happened at the end of my period for 1-2 days then everything was clear. I'm 26 and this is my first pack ever and i'm on my 17th day but i noticed today that the brown discharge is increasing and becoming more red and less viscous resembling the period more .. so what do i do??
do i stop the pill now or continue until the pack is over then take the break??
Also due to the fact that I started Yasmin on the 1st day of my last period, that caused my cycle to shift ... now it's 1 week earlier (1 week + 4 days if i'm having my period now) so it is going to ruin my honeymoon plans, can i do anything about that can i change the timing of my period that is if i'm not having it now??!